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Battery Charger Question

Thos

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Feb 14, 2021
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Hi guys;
I have a $50.00 battery charger that I got from a local hardware store for charging my 12v car battery. It's called an "intelligent" battery charger. It has a digital monitor that can be switched from showing a display of current input to voltage input to immediate battery capacity percentage during charging. It has an automatic battery "reconditioning" function and a button for varying the charge rate from 2A to 8A or 12A. Or you can set it to automatically vary the charge rate between 2 and 12amps.
Now I have just bought an SOK 12v206amp/hr battery for my motorhome. So of course I want to get a good battery charger to charge it when the solar input is inadequate. I checked out the battery chargers that Will recommends and they cost three to six times more than the $50 dollar one I got for my car battery yet they have no digital display of current or voltage input or even battery capacity during charging.
So is it really necessary to spend the extra money on a battery charger that is recommended for LiFePO4 batteries or is OK to charge my new LiFePO4 battery with a regular car battery charger?
Thos in British Columbia
 
I have a $50.00 battery charger that I got from a local hardware store for charging my 12v car battery.
Its charge profile is almost certainly only for lead acid. So it won't completely get your LiFePO4 battery fully charged but will probably get you most of the way there.

Do you know what the charge voltage is or anything about its charge profile?

I don't think it will harm your LiFePO4 charging it but I'd be cautious about leaving it on after charging stops as it may float at an elevated level.
 
I would not risk using $50 charger not really made for LifePO4 on $500 or more battery pack.
I also wonder about the ""reconditioning" function, it sounds like desulfate function with high Voltage pulse.
 
Certainly Ok to use it one trip and/or just for an emergency. Worst case the BMS will go to protect mode.
Although 12 amps is a bit slow.

After a few trips you may decide to do something else. Maybe even connect to the MH charging system.
 
My "smart" car battery charger gets pretty confused at times and goes into "reconditioning" mode on its own sometimes. I've tried a few different ones, and finally gave up. Meaning I'm not impressed with any of them I've used.

No way I'd use one on a Lithium unless it was made for it...
 
I would not risk using $50 charger not really made for LifePO4 on $500 or more battery pack.
I also wonder about the ""reconditioning" function, it sounds like desulfate function with high Voltage pulse.
Actually, with Shipping and Tax the 12v206amp/hr SOK cost me just over $1300U.S. So I know that I shouldn't think twice about getting a good battery charger. And yes, the "reconditioning" function is probably desulphation with a voltage pulse but that shouldn't ever engage with the LiFePO4 battery.
So I better get a charger that's designed for a Lithium battery and a proper monitor as well.
 
Actually, with Shipping and Tax the 12v206amp/hr SOK cost me just over $1300U.S. So I know that I shouldn't think twice about getting a good battery charger. And yes, the "reconditioning" function is probably desulphation with a voltage pulse but that shouldn't ever engage with the LiFePO4 battery.
So I better get a charger that's designed for a Lithium battery and a proper monitor as well.
Its charge profile is almost certainly only for lead acid. So it won't completely get your LiFePO4 battery fully charged but will probably get you most of the way there.

Do you know what the charge voltage is or anything about its charge profile?

I don't think it will harm your LiFePO4 charging it but I'd be cautious about leaving it on after charging stops as it may float at an elevated level.
I just press a button and it displays the charging voltage which was 14.8 volts that last time I looked. I don't know what the charge profile is. Press the button again and it tells me how much current is going in with a different button to vary the charge rate.
I don't like the idea of it floating at an elevated level though. I want to try to preserve battery life by not blasting it up to 100% every time I charge it so I need a charger that can be set to stop charging when the battery reaches a certain voltage. Can an MPPT be set to do that and also set to stop battery drainage at a certain voltage?
 
Because this charger has the "reconditioning function", I would never connect it to an LiFePO battery. Depending upon what they really mean by "reconditioning function" it could damage the battery. Not worth the risk in my opinion.
 
Sorry to say BUT it will HARM the LFP, Reconditioning is Pulse Equalization and BAD for Lithium. It can cause some BMS' to trip and others not resulting in damage.
LFP requires 2-Stage Charging: CC (Constant Current) which can get you to 90% & CV (Constant Voltage) to finish the last 10% as that needs variable amps as amps taken decreases as charge reaches full saturation. BTW: FLOAT = Constant Voltage/variable current.
Normal AMP CUTOFF (End-Amps / TailCurrent) is 0.05C of AH Rating which for 206AH Battery is 10.3 Amps.

The MAX Charge Rate for the 12V/206Ah is 50A per their site. Which is as expected but note that @ 50A the odds of runner cells is greatly increased, a more conservative 30-40A Charge rate will keep them more in control.

Even more importantly, the Charge Profile used for LFP is pretty simple BUT almost all prebuilt makers want to "push the edge" for numbers. The ONLY ones that work with are big commercial company battery packs by BattleBorn, Simpliphi, Relion, Rolls Surette etc. Because they use perfectly Matched, Batched & Binned premium cells (hence the costs being so high).
SOK, AmperTime also use good quality grade A cells BUT not the same class as the Big Commercial companies use, otherwise they'd price themselves out of the market.

DO NOT Charge these SOK batteries to 14.6V (3.650Vpc per cell) anything above 3.525 is a WASTE ! Charge it to death @ 3.650VPC and without triggering a runner, within one hour of the charge stops, the cells WILL settle to 3.550 +/-, within 2 hours they'll be close to 3.500 +/-. Below 2.850Vpc and above 3.450 only represents <5% of gross AH capacity. LFP Nominal Voltage is 3.200Vpc, Working Voltage is flat from 3.000-3.400Vpc and with fully matched & batched cells that extends to 2.850-3.450Cpc.
Vpc = Volts per cell. X4 for 12V, X8 for 24V and X16 for 48V.

Here is a Charge profile I use on 24V which will give you a better idea of a conservative profile which will not stress the batteries, prevent HVD (Hi Volt Disconnects) and allow the cells within the packs to top off and balancer out "politely".
All equipment MUST BE Voltage Corrected & Calibrated (VERY IMPORTANT) see link in my signature on how to do it.
Divide Values X2 for 12V. Multiply X2 for 48V.
Absorb:
28.2 for 15 minutes (3.525vpc) (some call this boost)
Equalize: OFF
Float 27.9V (3.4875vpc)
MIn Volts: 22.0 (2.750vpc)
Max Volts: 28.7 (3.5875vpc)
Rebulk Voltage: 27.7 (3.4625vpc)
End Amps: 14A (*1)

(*1): End Amps is calculated from the Highest AH Battery Pack in a Bank. IE: 200AH X 0.05 = 10A 280AH X 0.05 = 14A.
NB: Victron Forum discussion says EndAmps = TailCurrent
This get's the bank charged to full with high amps (Constant Current) and then float (Constant Voltage) tops off so the cells are on average between 3.475-3.500. I am running 7/24/365 so float is used up by the Inverter + provides whatever the packs will take to top off.

** Coulumbic Efficiency for LFP is 99%

Hope it helps, Good Luck.
Steve
 
Maybe post the charger model number or a picture. Best to know what we are working with. Good chance it is just a simple charger.
 
Hi guys;
I have a $50.00 battery charger that I got from a local hardware store for charging my 12v car battery. It's called an "intelligent" battery charger. It has a digital monitor that can be switched from showing a display of current input to voltage input to immediate battery capacity percentage during charging. It has an automatic battery "reconditioning" function and a button for varying the charge rate from 2A to 8A or 12A. Or you can set it to automatically vary the charge rate between 2 and 12amps.
Now I have just bought an SOK 12v206amp/hr battery for my motorhome. So of course I want to get a good battery charger to charge it when the solar input is inadequate. I checked out the battery chargers that Will recommends and they cost three to six times more than the $50 dollar one I got for my car battery yet they have no digital display of current or voltage input or this site even battery capacity during charging.
So is it really necessary to spend the extra money on a battery charger that is recommended for LiFePO4 batteries or is OK to charge my new LiFePO4 battery with a regular car battery charger?
Thos in British Columbia
I am also here for the same question
 
Hi guys;
I have a $50.00 battery charger that I got from a local hardware store for charging my 12v car battery. It's called an "intelligent" battery charger. It has a digital monitor that can be switched from showing a display of current input to voltage input to immediate battery capacity percentage during charging. It has an automatic battery "reconditioning" function and a button for varying the charge rate from 2A to 8A or 12A. Or you can set it to automatically vary the charge rate between 2 and 12amps.
Now I have just bought an SOK 12v206amp/hr battery for my motorhome. So of course I want to get a good battery charger to charge it when the solar input is inadequate. I checked out the battery chargers that Will recommends and they cost three to six times more than the $50 dollar one I got for my car battery yet they have no digital display of current or voltage input or even battery capacity during charging.
So is it really necessary to spend the extra money on a battery charger that is recommended for LiFePO4 batteries or is OK to charge my new LiFePO4 battery with a regular car battery charger?
Thos in British Columbia
I have a Motor Caravan which I don't tend to use in the winter and I tend to forget to ensure the vehicle and leisure batteries remain charged so as a result they go flat, Some time ago I bought what was called a smart battery charger from a national company which I won't name at the moment. The battery went flat, the charger didn’t work and a mate told me that smart chargers won't charge flat batteries. Would anyone care to recommend a normal old fashioned battery charger?
 
Some of the battery charger will check to see if there is at least 8 ~ 10V on the battery before it will activate the charging circuit, so if if the battery is really low then the charger will not try to charge dead battery, or if the BMS has gone into low Voltage shutdown which means the charger can't wake up the battery, but the Victron charger can be used to wake up the BMS.
The user manual should tell you what the requirement of the battery Voltage needs to be for the charger to work.
Victron smart battery charger will try to charge fully discharged battery by performing low current charging first.
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